Sourcing Earbud drivers

So I have been using Sennheiser MX70 earbuds over the years (gone through 3 pairs), I find them on ebay then I recable (the green wire that comes with them is short and falls apart fast) them use them until the drivers are spent. What I want to do is find a source for good sounding earbud drivers around the same size as the sennheiser MX70s and order them in bulk so I can just swap out drivers as they go bad. Anyone know where I can find earbud drivers in bulk?